Multilayer insole

ABSTRACT

Multilayer insoles made of several layers of polymeric materials and used for insertion into footwear, for example, for hygienic and orthopedic purposes. Multilayer insoles having increased manufacturability, absorption properties and low cost of environmentally friendly raw materials obtained from renewable sources.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Ukrainian Utility Model Number 146541 filed Feb. 24, 2021. The contents of this application are incorporated by reference into this application in its entirety.

FIELD OF THE INVENTION

The present invention relates to multilayer insoles, namely insoles made of several layers of polymeric materials, which can be used for insertion into footwear, for example, for hygienic and orthopedic purposes.

BACKGROUND OF THE INVENTION

Current known rubber insoles that decompose easily are described in CN 110240734 A, which describes a foamed composition with natural rubber, which contains 91-94% of natural rubber and a mixture of fatty acids, ash, protein and sugars, and also includes Chinese herbal medicine, calcium nanocarbonate, calcined kaolin, powdered talc, naphthenic oil, zinc oxide, stearic acid, foaming agent, paraffin, anti-abrasive agent, yellowing resistance agent, accelerating agent and sulfur in the following mass ratios:

-   -   foamed composition with natural rubber—100     -   Chinese herbal medicine—25     -   calcium nanocarbonate—25     -   calcined kaolin—20     -   talc powder—25     -   naphthenic oil—25     -   zinc oxide—5     -   stearic acid—5     -   foaming agent—10     -   paraffin—1     -   anti-abrasive agent—5     -   yellowing resistance agent—2.5     -   accelerating agent—0.5     -   sulfur—2.

The disadvantages of this known composition include low manufacturability, high complexity and long total duration of operations required for its manufacture, high cost, as well as harmful health effects due to the composition of the components from which this composition is made.

The composition described in CN 110240734 A determines the performance of many complex and long operations, such as the manufacture of Chinese herbal medicine, which in this case is a mixture of pepper, wormwood, blackhead, gutuiniya cordate, Zanthoxylum bungeanum, mandarin peel, grapefruit peel, cinnamon and bergamot, integration of Chinese herbal medicine into a foamed solution from which a foamed composition with natural rubber is formed, with the participation of many excipients and at a temperature of 105-115° C. with vigorous stirring, curing and vulcanization of the mixture at 155-160° C. and at a pressure of 15-20 MPa, which accordingly requires devices that are complex in design and use. Failure to comply with the temperature regime and the established ratio of components slows down the production of the insole and impairs its performance.

The need to use naphthenic oil (which is carcinogenic), as well as anti-abrasive agent, yellowing agent, accelerating agent, and their presence in the finished product increase the cost and reduce the manufacturability of this known composition due to the high cost of substances used as the above agents. In addition, despite its natural origin, natural rubber has a higher cost compared to other bio-based polymers as it is produced in limited quantities in a limited range of geographical areas. The high content of natural rubber in the foamed composition can cause allergic reactions in a user, because natural rubber is well known for its allergenic properties.

Additional known insoles made of composite injection foamed flexible material are described in WO 2019226719 A1, which includes such bio-based polymers as polylactic acid, polybutylene adipate-terephthalate, polycaprolactone, polyhydroxyalkanoate, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate, or thermoplastic starch in admixture with at least one uterine starch solution and cellulose acetate.

The disadvantages of these known compositions are low manufacturability, high complexity and long total duration of operations required for its manufacture, high cost, low performance properties, in particular adhesion to the inner surfaces of shoes, abrasion resistance, and cushioning properties due to the composition of the components.

Like the known compositions described above, the insoles described in WO 2019226719 A1 contain components that have a high cost due to the high cost of resources, time, labor and energy to manufacture them to form an insole, which increases the cost and reduces the manufacturability. In particular, the production of uterine starch solution, like the manufacture of any superconcentrate, requires the use of complex equipment, many complex operations and high consumption of raw materials. The formation of the above bio-based polymers is also complex, excessively time consuming and costly. In fact, bio-based polymers described in insoles made of composite injection foamed flexible material are described in WO 2019226719 A1 are selected as the basis for creating a composite injection foamed flexible material solely to mimic the properties of ethylene vinyl acetate and products thereof, which, despite a number of advantages, are characterized by low abrasion resistance, low adhesion to surfaces, which they adjoin, as well as reduced depreciation properties.

In addition, the formation of the composite injection foamed flexible material with the above composition of components also requires expensive and difficult to use equipment, in particular a twin-screw extruder and injection molding plant, which requires complex interaction of many complex elements in execution and use, dynamic temperature control in its components, the formation of supercritical fluid, gas back pressure to control the expansion of the mixture of components, and requires many complex in performing operations with the above equipment, which causes low manufacturability, high cost and high time for its production.

US 2017183469 describes a multilayer insole, which includes a base made with the possibility of fitting to the inside of the sole of the shoe and made of solid polyurethane with the inclusion of 1-25% of the biomass of algae containing sulfated polysaccharides, foam layer, which is located above the base and made of foamed polyurethane with the inclusion of 1-25% of the biomass of algae containing sulfated polysaccharides, and includes a fabric layer, which is located above the foam layer and is made of polyester or polypropylene knitwear or cotton.

The disadvantages of this multilayer insole are low manufacturability, environmental unfriendliness, high complexity and long total duration of operations required for its manufacture, low absorption properties, high cost, which are due to the composition of the components from which the insole is made.

Despite the pronounced antimicrobial properties, the insole described in US 2017183469 is characterized by low manufacturability, long total duration of operations required for its manufacture, and high cost, as proper pre-treatment of algae that are part of it, obtaining biomass containing sulfated polysaccharides, in particular fucoidan, as well as the synthesis of components for the production of solid and foamed polyurethane in a well-known way from non-renewable raw materials, i.e. the synthesis of isocyanates and polyhydric alcohols, the integration of algal biomass into layers, made of polyurethane, require devices that are complex in design and in use, many complex operations and high costs of raw materials, time, labor and energy.

The starting material for the production of the above biomass is characterized by a complex extraction process in a limited number of areas, which also increases the cost of the original insole.

In addition, the extraction of oil and other raw materials from non-renewable sources for the production of polyurethane, which is part of the known insoles, harms the environment by polluting it, in particular due to significant carbon dioxide emissions, indicating low environmental friendliness.

In addition, the insole described in US 2017183469 has low absorption properties, as polyester fibers, polypropylene knitwear and cotton fabrics absorb a small amount of moisture, which, in turn, when using these materials in the fabric layer of the insole, leads to reproduction of microorganisms, odor accumulation, user odor and rapid damage to the tissue layer.

SUMMARY OF THE INVENTION

The technical tasks of the claimed invention are to create a new multilayer insole that has increased manufacturability, absorption properties and low cost of environmentally friendly raw materials obtained from renewable sources.

The solution of the technical problem is achieved by the multilayer insole, which includes a base that is made to fit to the inside of the sole of the shoe, a foam layer, which is located above the base, and a fabric layer, which is located above the foam layer. In accordance with the present invention, the base is made of rigid bio-based polyurethane, the foam layer is made of foamed bio-based polyurethane, and the fabric layer is made of at least lyocell or fibers of bio-based polyamide.

Also, according to the invention, the multilayer insole comprises a lead layer located between the base and the foam layer, which is made of a bio-based thermoplastic polymer and can be arranged at least under arch of the foot.

The fabric layer may be made of a mixture of lyocell or bio-based polyamide and coal of plant origin.

In some embodiments, the base contains at least one elastic insert, which is made of bio-based polymer and may be configured to fit to the inside of the sole of the shoe.

The technical result of the present invention is increased manufacturability with the exception of expensive and environmentally harmful operations for the extraction of raw materials from non-renewable sources and ensuring the use of biomass and organic waste, environmental friendliness of the insole, improving the absorption properties of the insole and reducing cost.

These listed advantages of the present invention are achieved due to the properties of raw materials from which bio-based polymeric materials are made, which are part of the elements of the claimed insole, as well as due to the absorption properties of lyocell or bio-based polyamide fibers.

The claimed insole has increased environmental friendliness because the raw material for the manufacture of rigid and foamed polyurethanes, as well as lyocell or fibers from bio-based polyamide is a raw material that contains increased amount of carbon isotope C14. Due to the inherent accumulation of this carbon isotope in living plants and living organisms in general during metabolic processes, as well as the shorter lifespan of this isotope of carbon compared with the stable isotope C12, raw materials from renewable sources have an increased amount of carbon isotope C14 compared to raw materials from non-renewable sources such as oil, natural gas, hard coal and lignite etc., which contain exclusively the carbon isotope C12. Using for biobased polymers raw materials from renewable sources, preferably vegetable raw materials such as cereals, vegetable oils, such as soybean oil, castor (or so-called castor) oil, linseed oil, tung oil, or organic waste, such as debris consisting of plant parts, oilcake, etc., makes it possible to eliminate expensive and environmentally harmful operations for the extraction of raw materials from non-renewable sources, such as oil and natural gas fields, as well as to get rid of emissions of harmful substances that occur during the processing of these raw materials from nonrenewable sources into the environment. The process of processing organic waste and biomass to create bio-based polymers can be considered as a condition and an important factor in a cyclical economy, as this approach converts the flow of “resource-production-use-waste” in a closed cycle, which also increases the environmental friendliness of the insole.

At the same time, the low cost of vegetable raw materials, in particular vegetable waste, compared to the cost of oil, natural gas and hard coal and lignite increase the manufacturability of the claimed insole and reduce its cost.

The claimed insole has increased manufacturability and reduced cost because the manufacture of plant raw materials of bio-based polymers, in particular biobased polyurethane, lyocell and bio-based polyamide, does not require the use of complex expensive specialized equipment and expensive reagents for chemical processes, long operations of processing or reprocessing of primary raw materials, a set of successive chemical reactions in difficult to regulate conditions, the use of high temperatures and high pressure, etc.

The list of operations required to obtain vegetable raw materials, such as diisocyanate and polyhydric alcohols, which, in turn, are required for the synthesis of bio-based polyurethane, is much smaller than the list of operations required to obtain diisocyanate and polyhydric alcohols from petroleum or its processing products, or from other similar raw materials from non-renewable sources. In general, obtaining a bio-based polyurethane for the base and the foam layer, as well as fabric from the fibers of the bio-based polymer, such as lyocell or bio-based polyamide, from raw plant materials are cheaper and simpler than the production of polymers from petroleum or other similar raw materials from non-renewable sources, due to the fact that cellulose, lactic acid, diisocyanate, polyhydric alcohols and other substances for the production of bio-based polymers can be removed from vegetable raw materials in a short time using simple equipment and auxiliary materials, as well as to make biobased polymers from these substances, which accordingly reduces the cost of the claimed insole and increases its manufacturability.

The claimed insole has increased absorption properties because the lyocell and biobased polyamide fibers from which the fabric layer of the claimed insole is made have higher absorption properties than the well-known polyester, cotton or polylactide fabrics used for the fabric layer of insoles, in particular known insoles. In turn, due to the increased ability to absorb moisture, the fabric layer of the claimed insole can reduce the smell of sweat, damage to the fabric due to moisture, reduce the humidity of the insole to prevent the reproduction of microorganisms and ensure comfortable wearing by the user.

Thus, both lyocell and bio-based polyamide fibers are environmentally friendly materials and are bio-based polymers that are made from inexpensive raw materials and with reduced time, energy, labor and materials for processing raw materials and making fibers of these bio-based polymers, which increases manufacturability and reduces the cost of the claimed insole.

In some embodiments, the insole contains a lead layer located between the base and the foam layer, which is made of bio-based thermoplastic polymer and may be located at least under the arch of the foot, which allows to increase the orthopedic properties of the claimed insole, in particular to ensure correct anatomical position.

Execution of the fabric layer of the claimed insole from a mixture of lyocell or bio-based polyamide and coal of plant origin allows to expand functionality of the claimed insole as it provides the insole with antibacterial properties of vegetable charcoal, in particular bamboo charcoal or charcoal formed during the processing of coffee beans.

Particles of coal of plant origin integrated into the fibers of the tissue layer can destroy both microorganisms that have been absorbed by the tissue layer together with moisture and microorganisms on the user's foot, leaving no harmful substances on the user's skin. At the same time, coal of plant origin is cheap, which increases manufacturability and reduces the cost of the claimed insole.

Making the base with at least one elastic insert, which is made of biobasic polymer and may be configured to fit to the inside of the sole of the shoe, increases the cushioning properties of the claimed insole, providing ease of use and reducing fatigue from long walks.

Other objects of the invention and its particular features and advantages will become more apparent from consideration of the following drawings and accompanying detailed description. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The design of the claimed multilayer insole is explained by the following drawings:

FIG. 1 is a schematic illustration of a longitudinal cross-sectional view of the multilayer insole of the present invention.

FIG. 2 is a schematic illustration of a longitudinal cross-sectional view of the multilayer insole of the present invention in the embodiment with a joint layer.

FIG. 3 is a schematic illustration of a longitudinal cross-sectional view of the multilayer insole of the present invention in the embodiment with elastic inserts of the base.

FIG. 4 is a bottom view of the multilayer insole of the present invention in the embodiment with elastic resilient inserts of the base.

DETAILED DESCRIPTION OF THE INVENTION

The application incorporates by reference the appendices attached herewith to the application in their entirety.

In the following description, numerous details are set forth for the purpose of explanation. However, one of ordinary skill in the art will realize that the invention may be practiced without the use of these specific details.

Bio-based polymers are derived from the biomass or issued from monomers derived from the biomass and may be, at some stage in their processing into finished products, shaped by flow. Vert, Michel (2012), Terminology for biorelated polymers and applications (IUPAC Recommendations 2012), Pure and Applied Chemistry, 84 (2):377-410. To define the bio-based part of polymer there is registered standard test described in ASTM D6866-08, Standard Test Methods For Determining The Biobased Content Of Solid, Liquid, And Gaseous Samples Using Radiocarbon Analysis. The difference between bio- and not biobased materials is typically in the content of C¹⁴ isotope in the total carbon content. This is commonly used as a marker that the polymer was produced on the base of biomass, not fossils (oil or gas) and thus is considered to be more eco-friendly because it reduces the carbon footprint of the production.

The drawings schematically show preferred but not exclusive embodiments of the claimed multilayer insole, which includes a base 1, a foam layer 2, and a fabric layer 3. In additional embodiments shown in other figures, the claimed insole may also include a composite layer 4 and elastic resilient inserts 5 of the base 1.

The base 1 may be made of rigid bio-based polyurethane, with the possibility of adhering to the inner side of the sole of the shoe and is necessary to form the structure of the claimed insole and give it a stable shape. Rigid bio-based polyurethane used in the base 1 can be, for example, bio-based polyurethanes Pearlbond™ ECO (also known as Lubrizol), Elastollan® manufactured by BASF, Renuva™ manufactured by Dow Chemicals, JEFFADD® manufactured by Huntsman, Recypol® manufactured by RAMPF, Econykol™ manufactured by Mitsui Chemicals & SKC Polyurethanes Inc, and other suitable materials. In some embodiments, the bio-based polyurethane material used for the base 1 has a Shore Hardness in the range of about 80 Hs on Shore A scale to about 80 Hs on Shore D scale.

In a preferred embodiment of the claimed insole, the base 1 comprises at least one elastic insert 5, as shown in FIGS. 3 and 4, which is made of a bio-based polymer and can be adhered to the inside of the sole of the shoe. The bio-based polymer of the elastic resilient insert 5 of the base 1 may be, for example, polyurea or a thermoplastic elastomer of copolymers of polyethylene and polypropylene, and other suitable materials. The inner volume of the elastic inserts 5 of the base 1 can be filled with gel. In the embodiment shown in FIGS. 3 and 4, the insole 1 comprises two elastic inserts 5, one positioned in the frontal areal of the insole and the other positioned in the heel area of the insole. The elastic inserts 5 perform two functions. One is to absorb the strike energy when the user concentrates his or her weight on the heel and on toes. The other is to fixate the sole inside the shoe by sticking to a surface.

The multilayer insole also includes a foam layer 2 located above the base 1. The foam layer 2 is preferably made of foamed bio-based polyurethane and is designed to cushion the user's foot. In a preferred embodiment, the foamed layer 2 takes the shape of a user's foot, and the foamed bio-based polyurethane is a so-called shape memory foam. Such foamed bio-based polyurethane can be, for example, Bio-Pur® manufactured by Amerisleep. In further embodiments, a liquid two-part composite that hardens when mixed can be used to make the foam layer 2. The first part of this composite has the main part—polyol, which may be of brands Sovernol® (BASF), Sweetch (Emery), or BiOH® (Cargill). To this part such additives as dyes, fillers, surfactants (for foam density regulation) are introduced. The second part of the composition is isocyanate. In some embodiments, the foamed bio-based polyurethane material used for the foam layer 2 has a Shore Hardness in the range of about 15 Hs to about 70 Hs on Shore A scale.

The multilayer insole further includes a fabric layer 3 located above the foam layer 2 between the foam layer and the user's foot, as seen in FIGS. 1-3. The fabric layer 3 may be made with lyocell or fibers of bio-based polyamide and has a hygienic and absorbent functions. Lyocell may be, for example, Tencell™ fiber manufactured by Lenzing, and bio-based polyamide may be, for example, bio-based polyamides known as PA11 or polyamide-11, Rilsan® manufactured by Arkema, EVO® manufactured by Fulgar, or Sorona® manufactured by DuPont. In some embodiments, lyocell and/or bio-based polyamide fibers are not used alone, but instead in mixture with cotton fibers. A percentage of cotton in the mixture may be in the range of about 25% to about 75%. A higher content provides for better absorption, whereas a lower content provides for better durability. An approximate weight of the fabric layer 3 is about 0.4 to about 0.6 grams, wherein an approximate weight of the entire multilayer insole 1 is several tens of grams. The fabric layer 3 may advantageously provide the sweat absorption characteristics to the claimed multilayer insole. Furthermore, the material used for the fabric layer 3 may include one or more suitable anti-bacterial agents to provide anti-bacterial properties to the insole.

In some preferred embodiments, the fabric layer 3 is made of a mixture of lyocell or bio-based polyamide and charcoal of plant origin. The charcoal is preferably integrated into the fibers of lyocell or the bio-based polymers during their manufacture. For example, the charcoal may be integrated inside the fibers at a stage of making those fibers from a polymer melt. It may be added there in a form of fine powder, uniformly distributed with a help of twin screw extruder, and resultant melt is directed into dies to form threads. This results in the intrinsic porosity of such fibers since the carbon particles have internal free volume, so they are absorbent, or at least more absorbent than the original polymer. This provides the advantage of this material being able to absorb sweat and other moisture. Any suitable types of charcoal of plant original may be used in accordance with the invention. For example, bamboo-based charcoal is known to have both absorption and antibacterial properties and may be used for the fabric layer.

As illustrated in FIG. 2, the insole 1 may also include a composite layer 4 that is located between the base 1 and the foam layer 2. The composite layer 4 is preferably made of a bio-based thermoplastic polymer. Suitable bio-based thermoplastic polymers may be, for example, bio-based thermoplastic polyurethane Ellastolan® manufactured by BASF, bio-based ethylene vinyl acetate SVT manufactured by Braskem, polystyrene thermoplastic elastomer Megol™ Bio manufactured by Trinseo, thermoplastic elastomer Terraprene® manufactured by FKuR Polymers GmbH, and Dryflex Green manufactured by Hexpol, as well as other suitable materials. In some embodiments, the composite layer 4 is located at least under the arch of the wearer's foot.

The composition of the bio-based thermoplastic polymer of the composite layer 4 may include wood or cellulose fibers. Any known suitable wood or cellulose fibers may be used. The advantages of adding wood or cellulose fibers to the composition of the composite layer 4 include making the layer stiffer, more resistant to dynamic loads and more eco-friendly.

The layers of the claimed multilayer insole can be bonded to each other with an adhesive, can be sewn or connected by soldering, or other similar method. For example, an acrylic adhesive may be used to provide sufficient adhesion between the composite layer 4 and the foam layer 2 to avoid their disintegration. Any other suitable types of adhesive may be used as well.

The present inventors discovered that insoles that contain TPU make a crackling sound when used with some types of shoes. This problem is caused by the “sticking” of TPU arch surface to inner surfaces of shoe, in other words, TPU can be too rubbery. To solve this problem, the present inventors developed a surface texture that assists in decreasing the contact between the show and the sole surface. In certain embodiments, the surface texture includes parts having different rigidity.

In certain embodiments, the surface is made of materials that are textured.

The claimed multilayer insole is used as follows. First, the claimed multilayer insole is placed in the shoe so that the base 1 is adjacent to the inner side of the sole of the shoe and extends over its entire area, and the fabric layer 3 is the uppermost location of the layer of the claimed insole. In an embodiment of the claimed multilayer insole with the elastic resilient inserts 5 of the base 1, as shown in FIG. 3, their location in the above-described attachment preferably corresponds to the pad of the foot and the heel of the user. Also, in the embodiment of the claimed multilayer insole with the composite layer 4, the composite layer in the above-described attachment corresponds to the arch of the user's foot and the areas of the foot close to the arch.

After inserting the claimed insole to the shoe, the user puts on the foot of the shoe. In this case, their foot is adjacent to the fabric layer 3. When wearing a shoe with the claimed insole attached to it, the fabric layer 3 absorbs sweat and, in some embodiments, disinfects the user's foot, and the foam layer 2 absorbs the load on the sole and the claimed insole. In some embodiments, the composite layer 4 is placed in the arch of the foot and forms its anatomically correct outlines. Also, in some embodiments, the elastic inserts 5 of the base 1 further absorb the load on the sole and the claimed insole, especially during intense walking or running.

In certain embodiments, the invention includes elastic inserts within recesses in the based and/or the foam layer.

In certain embodiments, the foam layer is configured to receive the base.

In certain embodiments, the base is made of rigid materials, while the foam layer is made of flexible or softer materials.

In certain embodiments, elastic inserts are made of elastic materials that have greater elasticity than the base and foam layer.

In certain embodiments, the surface structure includes materials that help decrease the squeaking of shoes.

In certain embodiments, the surface structure includes various configurations such as anisotropic, fractal anisotropic, isotropic, and others.

In certain embodiments, the direction of the texture coincides with the direction of the insole movement during use.

In certain embodiments, line thickness of not less than 0.5 mm, and the distance between the lines of not more than 0.8 mm, and depth of not less than 1 mm is provided.

The proposed technical solution is industrially applicable, as it does not contain any actions, operations or measures that cannot be reproduced at the present stage of technical development.

Other objects of the invention and its particular features and advantages will become more apparent from consideration of the following drawings and accompanying detailed description. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

Having thus described several embodiments for practicing the inventive method, its advantages and objectives can be easily understood. Variations from the description above may and can be made by one skilled in the art without departing from the scope of the invention.

Accordingly, this invention is not to be limited by the embodiments as described, which are given by way of example only and not by way of limitation. 

What is claimed is:
 1. A multilayer insole comprising: a base configured to fit to an inside of a shoe sole; a foam layer located above the base; and a fabric layer located above the foam layer; wherein the base comprises a rigid bio-based polyurethane; wherein the foam layer comprises a foamed bio-based polyurethane; and wherein the fabric layer comprises at least one of lyocell and bio-based polyamide.
 2. The multilayer insole of claim 1, further comprising a composite layer located between the base and the foam layer, wherein the composite layer comprises a bio-based thermoplastic polymer, and wherein the composite layer is configured to support an arch portion of a user's foot.
 3. The multilayer insole of claim 2, wherein the bio-based thermoplastic polymer comprises wood or cellulose fibers.
 4. The multilayer insole of claim 1, wherein the fabric layer comprises a mixture of at least one of lyocell and bio-based polyamide, and coal of plant origin.
 5. The multilayer insole of claim 4, wherein particles of coal of plant origin are integrated into fibers of the fabric layer.
 6. The multilayer insole of claim 1, wherein the base comprises at least one elastic insert made of a bio-based polymer.
 7. The multilayer insole of claim 6, wherein the bio-based polymer of the at least one elastic insert is selected from a group consisting of polyurea and a thermoplastic elastomer of copolymers of polyethylene and polypropylene.
 8. The multilayer insole of claim 6, wherein an inner volume of the at least one elastic insert is filled with gel.
 9. The multilayer insole of claim 1, wherein the foam layer is configured to cushion a user's foot
 10. The multilayer insole of claim 1, wherein the foamed bio-based polyurethane is a shape memory foam.
 11. The multilayer insole of claim 1, wherein the fabric layer has a hygienic and absorbent function.
 12. The multilayer insole of claim 1, wherein the bio-based polyurethane base is selected from a group consisting of bio-based polyurethanes Pearlbond ECO (also known as Lubrizol), Renuva manufactured by Dow Chemicals, JEFFADD manufactured by Huntsman, Recypol, Econykol manufactured by Mitsui Chemicals & SKC Polyurethanes Inc.
 13. The multilayer insole of claim 1, wherein the shape memory foam is Bio-Pur manufactured by Amerisleep.
 14. The multilayer insole of claim 1, wherein the lyocell is tencell fiber manufactured by Lenzing Gruppe or Everest.
 15. The multilayer insole of claim 18, wherein the thermoplastic polymer is selected from a group consisting of bio-based thermoplastic polyurethane Ellastolan, bio-based ethylene vinyl acetate SVT manufactured by Braschem, polystyrene thermoplastic elastomer MEGOL BIO manufactured by Trinseo and thermoplastic elastomers Terraprene manufactured by FKuR Polymers GmbH and Dryflex Green manufactured by Hexpol.
 16. A method of making a multilayer insole comprising the steps of: providing a base configured to fit to an inside of a shoe sole; placing a foam layer above the base and adhering the foam layer to the base; and placing a fabric layer above the foam layer and adhering the fabric layer to the foam layer; wherein the base comprises a rigid bio-based polyurethane; wherein the foam layer comprises a foamed bio-based polyurethane; and wherein the fabric layer comprises at least one of lyocell and bio-based polyamide.
 17. The method of making a multilayer insole of claim 16, further comprising the step of placing a composite layer between the base and the foam layer and adhering the composite layer to the base and the foam layer, wherein the composite layer comprises a bio-based thermoplastic polymer, and wherein the composite layer is configured to support an arch portion of a user's foot.
 18. The method of making a multilayer insole of claim 16, further comprising the step of placing at least one elastic insert in the base, wherein the at least one elastic insert is made of a bio-based polymer.
 19. The method of making a multilayer insole of claim 16, further comprising the step of filling an inner volume of the at least one elastic insert with gel. 